Paving composition and process of making the same



UNITED STATES PATENT OFFICE.

CHARLES ALFRED CABLES m: CAUDEMBEBG, OF NICE-GARE, FRANCE.

ravnm comrosr'rron am) raocass or maxme'rrm sum.

Be it known that I, CHARLES ALFRED Cams on CAUDEMBERG, a citizen ofFrancef residin at Nice-Gare, in the Province 0 Alpesaritimes, Republic of France, have invented a new and useful Paving Compos1- tion and Process of Making the Same, of which the followin is a specification.

This invention re ates to a pavlng compound and process of making the same. It has. for its object the improvement of procasses of preparing combinations of all kmds of bituminous substances with rubber, the bitumens being in the form' ofjasphalt, asphaltic rock, residues of the dlstillatlon of oils of naphtha and petroleum, etc.

It is well, known to those skilled 1n the art, that rubber dissolved in gasolene can be combined with bitumen, impregnating the pulverized calcareous grains of the asphalt' (asphaltic rock) to form a st1eky mass which permits the agglomeratlon of the asphalt by simple compression.

The above process, which practically consists of diffusing through a mass of powdered as halt, a solution of rubber in gasolene or ike solvent and efiecting the compression before the solvent evaporates, presents many defects. The solvent not only does not dissolve more than a small proportion of rubber, but certain elements of. the gum remain insoluble and form a. large deposit. Besides, the special qualities of therubber, especially its glutinous quality, are visibly altered and this alteration becomes more marked with time. Again, the dissolving action of the solvent on the bitumen is very slow, and this action (indispensable for the combination) is further retarded because of the gum content of the solution. Finally, the boiling point of. this solvent, and its volatilization is all the more rapid,

since it is promoted by mixing it with the.

powder, WlllCh enlarges the evaporating surace.

The result is that the uantit of rubber that can be incor ra in the asphalt, under these conditions, is strictly limited. It cannot exceed 30 or 40 grams per 100 kilograms of powder, and even then its combination with the bitumen is incomplete.

Patented Nov. 1, 1921.

Serial no. 487,587.

Although with this weak proportion the compression can be efiected and the cohesion of certain kinds of asphalt powders can be insured, (which powders on account of their binding nature and a special addition of bitumen are particularly adapted to the process,) a number of other powders do not lend themselves to this method, either because they have too great content of bitumen or because the character of the bitumen or that 0f the calcareous grains impregnated by it offers more resistance to the action of the solvent. Consequently the combination does not take place to the degree necessary to insure the cohesion before the solvent evapo rates. The same drawback occurs when the work takes place at a high tem rature, which accelerates the volatilizatlon. In fact, the inherent advantages of the bitumen-rubber combination are very little developed, and have no appreciable efiect.

The present invention permits the asphalt to be prepared for cold compression, under conditions insuring the entire incorporation of rubber into bitumen to a much greater degree, the method being adapted to the composition of various kinds of asphalt and to changing temperatures. It also permits the use of the rubber-bitumen combination in the preparation of all kinds of bitumens,

residues and mixtures to be poured hot.

The result is a colloidal substance, indefinitely malleable and compressible, having powerful cohesive properties and ofi'ering a fusion point much higher than bitumen. Thus there is made an industrial produ'ct entirely new, having the qualities of elasticity, impermeability and high resistance, entirely suited to cold compresslon and offering not only an important improvement for current use in hot applications, but, in one form, permittin repaving of streets, etc., by a method di erent from those now em loyed.

he process of this invention consists in effecting the solutions by means of mixtures exercising a strong and rapid solvent action on both rubber and bitumen, offering ahigh boiling point and not injurious to the molecular constitution or the qualities of the dissolved elements. In certain proportions,

these mixtures become non-inflammable, an indispensable condition for hot preparations, I

It has been found that such solvents can be obtained by adding to benzene or toluene, a tetrachlorethane in the proportion of 20% for cold preparations and 86% for hot ones,'theseproportions being capable of very slight variation. t

he formulas of the solutions are:

A:Tetrachlorethane 200 cc. Benzene or toluene 800 cc. Rubber -50 gr.

B:.Tetrach1orethane 860 cc.

" Benzone or toluene 140 cc. Rubber 50-75 gr.

The solutions thus prepared are incorporated in the asphaltic and b tuminous substances under various conditions, accord ing'to the method of application. The pro.

portion of the quantities of rubber is in conformity with the composition'of asphalt The quantity of solution to be mixed var-ies, according to its gum content, from 3 to 4 kilograms per 100 kilos of powder. According to the special case, the quantity of rubber is regulated by employing solutions more or less strong, from 2.50% to 5%. Weak solutions are mixed very rapidly. To incorporate thick solutions, one must effect the first impregnation with a light solution, which facilitates the absorption while softening the bitumen.

can beusedwith a 5% solution.

On leaving themixer the material is spread out in a bed of uniform thickness on a cOncrete or cement-foundation, already covered with light liquid cement. The material is compressed gradually but the use of a roller for this purpose is not desirable because it displaces the material s1dew1se and interferes with its adherence to the cement.

For the manufacture of agglomerations of asphalt compressed by pressure, the preparation is the same as above. The pressure will be regulated to 300 kilos per square centimeter of surface.

Example 25 The preparation 0: bitumens .Thus there can be used at first 500 to 1000 grams of a 2.50% solution and finally 2,000 grams stantly agitated.

The mlxture' thus obtained'can be used in several ways:

First. To prepare asphalt poured in a plastic state, the quantity of bitumen melted to be incorporated in the solution will be 5% of the quantity-of asphalt to prepare,

and the proportion of the solution B, 4 or 5 kilograms per 100 kilos of matter; the proportion :of rubber varying in respect to the fusion point desired, from 5% to 7.50%.

The bitumen-rubber mixture having been brought to the temperature of-100-120 degrees, the, plastic asphalt isintroduced, divided into successive portions, 11 to 150*180 degrees, .to efiect the cooking. uring this operation proper provision can be made for collecting the vapors of the solvents to save them.

' The product thus obtained can be adapted to various applications. It can be added to sand or gravel. In this case, thesesubstances are introduced, at the beginning of the cooking, in small quantities to prevent cooling the mass. This preparation is ad vantageously utilized for all the urposes for which the ordinary mass can used, as it has superior cohesion and resistance,

and also greater elasticity. It can also be used pure-for certain kinds of work, which represents an entirely newapplication of poured asphalt, based on its high point of fusion, which insures stability at temperatures over degrees, and does not involve the use of hard substances, indispensable for the ordinary poured preparation.

In practice, the two processes can be comrbined-by making a bed of the compound mixed with gravel and putting-alayer of the pure product thereon. The ure product is especially indicated for wor that must be absolutely waterproof and yet must be elastic or-yielding suchas terrace's,-bridge heads, etc. The fused substance is Simply poured out on the surfaces to be covered and flattened by means of wooden planks or the like.

Second. Bitumen-rubber, prepared as described, can also be used for bituminous concretes or-asphalt-macadam. in this kind of roads, either the natural bitumens can be used, freed from all earthy matter, or the residues of the distillation of etroleum. Melted bitumen, mixed in the ru ber solution in the proportion of 15-20 hlograms of solution per 100 of bitumen, is brought to the temperature of 150480 degrees and poured directly, in the proportion of 10-12 kil. per square meter, on a rocky foundation of 0.15-0.18 centimeters of thickness, previously placed on the earth and arranged evenly. The surface is covered with sand and a roller is passed over it.

The mixture of bitumen-rubber and pebbles may be made before it is applied. In certain instances, there is placed on this foundation a covering of the asphalt-plaster preparation, either pure or mingled with sand and fine gravel.

What is claimed is 1. A composition of matter for use as an industrial product, and resulting from the combination of bitumen with rubber, said rubber being contained in a solvent obtained by adding to benzene, tetrachiorethane in the proportion of about 20% for use when of fusion.

cold and about 86% for use when hot, there being approximately l1.50 of rubber to 100 of bitumen.

2. A composition of matter for use as an industrial product, and resulting from the combination of bitumen with rubber in a proportion of approximately 11.5O of rubber to 100 of bitumen, said composition having colloidal properties and a high. point In testimony that I claim the foregoing as my own, I have hereto affixed my signature in the presence of two witnesses.

CHARLES ALFRED CARLES dc CAUDEMBERG,

Witnesses:

DOUGLAS BOOTH, L. MOREAN. 

